This invention relates to an open-end spinning device which includes a spinning rotor. The present invention relates more particularly to an open-end spinning device which includes a spinning rotor having a bottom face, a lateral sliding face widening conically towards the bottom face and provided for the fibers which have been fed into the spinning rotor, and a fiber collecting groove between the bottom face and the sliding surface. The open-end spinning device further has a blast air opening in a stationary part of the spinning device adjacent to an inner chamber of the spinning rotor. This blast opening is provided so that fibers and foreign bodies can be blown out of the fiber collecting groove for purposes of cleaning the same.
It has been found that the fiber collecting groove in the case of spinning devices of this type can frequently only be cleaned in a very unsatisfactory manner by the jet of air from the blast nozzle. Fibers lying in the fiber collecting groove which are no longer bound up with the fibers which have been removed, are frequently intertwined or twisted by the air jet to form a fiber ring which cannot be separated owing to its inner cohesion and which, as a result of its outer dimensions, cannot be lifted independently from the fiber collecting groove.
To reliably free the spinning rotor of residual fibers and impurities in the fiber collecting groove by means of the air jet, it is proposed according to the present invention that the bottom face of the spinning rotor be provided with a shallow, concave curved portion between the axis of rotation of the spinning rotor and the fiber collecting groove, and that the axis of the blast opening be directed towards this inwardly curved portion of the bottom face.
The air jet in operation skims, in the manner of a fan, over the curved portion of the bottom face of the spinning rotor, reaches the fiber collecting groove below the fibers and foreign bodies deposited thereon and effectively lifts these over the sliding surface and the edge of the spinning rotor into the spinning chamber surrounding the spinning rotor, from where these fibers and foreign bodies are removed by suction.
The foregoing object, as well as others which are to become clear from the text below, is achieved in an open-end spinning device which includes a spinning rotor having an axis of rotation, a bottom face, a lateral sliding face conically widening toward the bottom face and intended for receiving fibers which have been fed into the spinning rotor. A fiber collecting groove is located between the bottom face and the sliding face. A blast air opening having an axis is disposed on a stationary part of the spinning device adjacent to an inner chamber of the spinning rotor for blowing fibers and foreign bodies from the fiber collecting groove to clean the same. A shallow, concave curve defining an inwardly curved portion of the bottom surface of the spinning rotor is provided between the axis of rotation of the spinning rotor and the fiber collecting groove. The axis of the blast opening is directed toward the inwardly curved surface of said bottom.
Advantageously, the axis of the blast opening is directed toward the bottom face of the spinning rotor at an acute angle. In many cases, it can also be advantageous for the axis of the blast opening to be directed generally tangentially onto the bottom face.
Advantageously, the bottom face of the spinning rotor possesses with respect to a plane perpendicular to the axis of rotation of the spinning rotor defined by the line of the largest diameter of the fiber collecting groove, a raised section on the axis of rotation and a depressed section between the axis of rotation and the collecting groove. In an especially advantageous embodiment, the deepest point of the depressed area in the bottom surface of the spinning rotor is located at a distance from the axis of rotation of the spinning rotor; this distance being greater than half the distance between the axis of rotation and the fiber collecting groove and being between two thirds and three quarters of the distance between the axis of rotation and the fiber collecting groove.
The difference in height between the highest point of the raised section and the deepest point of the depressed section in the bottom face of the spinning rotor in a direction parallel to the axis of rotation of the spinning rotor is advantageously between one twentieth and one tenth of the diameter of the fiber collecting groove.
Other objects, features and advantages of the present invention will be made apparent from the following detailed description of a preferred embodiment thereof which is provided with reference to the accompanying drawing.